Recent studies suggest a high prevalence of cognitive and psychiatric impairments in patients infected with Human Immunodeficiency Virus (HIV). New evidence in psychoneuroimmunology indicates that psychosocial deficits and psychiatric symptoms, including depression, may be immunosuppressive. Furthermore, alterations of the hypothalamic- pituitary-adrenal axis have been well documented in stress and major depression, and endocrine hormones of this axis are known to alter lymphocyte number and activity. Based on these findings, the present study will investigate the progression of psychiatric, psychosocial, neuropsychologic, neuroendocrine, and immune functioning in asymptomatic HIV-infected patients compared to seronegative controls. In addition, we will assess the impact of psychosocial and psychiatric variables on immune and endocrine function and disease progression. The sample will include 120 seropositive homosexual and hemophilia patients with 80 seronegative matched controls. Approximately one-third of our seropositive patients will be recruited from the UNC AIDS Clinical Study Group, which is studying the efficacy of zidovudine (ZDV). Subjects will also be recruited from the UNC Infectious Disease Service and associated AIDS-related clinical and research centers. Subjects will be followed for 5 years and assessed every 6 months. Using both linear and stochastic statistical models, we will assess the following: 1) the relationship of psychiatric and psychosocial variable at baseline and over time with HIV-related symptom progression and immune functioning; 2) the mediating roles of psychosocial assets and endocrine function in the relationship among psychiatric symptoms, immune function, and disease progression; 3) the prevalence of psychiatric and neuropsychologic symptoms in each of our subgroups; and 4) the effects of ZDV on neuropsychologic and psychiatric impairments. The results of this study should help in the planning for the health care needs of this expanding population, and aid both in understanding the psychoneuroendocrine-immune mechanisms underlying this immunocompromising disease as well as psychoneuroendocrine-immune mechanisms in general.